Flywheel magneto



y 17, 1966 s. M. TERRY Em, 3,252,021

FLYWHEEL MAGNETO Filed June 25, 1963 3 Sheets-Sheet l INVENTORS- 2STANLEY M. TEEPY BOB o- BUESON May 17, 1966 s. M. TERRY ETAL FLYWHEELMAGNETO 3 Sheets-Sheet 2 Filed June 25, 1963 INVENTORS. STANLEY P".TERRY BOB 0. EU 125 ATTOP/VEK May 17, 1966 s. M. TERRY ETAL FLYWHEELMAGNE'I'O 3 Sheets-Sheet 5 Filed June 25, 1963 INVENTORS. M TEEIZY BUT?SON STANLEY OB C) B BY 2 Z ATTOP/VEM United States. Patent Thisinvention relates to flywheel type magnetos or the like and hasparticular reference to the provision of a new and improved flywheeltype magneto which is particularly adapted to operation with automaticspark advance.

Small, high output gasoline engines are being applied in increasinglylarge numbers in a large variety of applications such as, for example,in lawn, garden and farm equipment.

In order to enhance the star-ting and to improve the high speedoperations of such engines, automatic spark advance i being increasinglyutilized thereon.

However, when automatic spark advance is applied to conventionalmagnetos, either the low speed or the high speed voltage output has beenfound to be inadequate or the advance change over has had to operate atexcessively high speed in order to generate adequate voltage afteradvance with resultant low torque at the lower speeds and loss ofoperating efiiciency of the engine.

An object of the present invention is to provide a new and improvedflywheel type magneto which is particularly adapted for operation withautomatic spark advance.

Another object of the invention is to provide a new and improvedflywheel type magneto of the type set forth which provides adequateignition voltage both for starting at low cranking speed and for highspeedoperation and which is designed to advance at relatively low enginespeeds to provide optimum engine torque output for acv celerating underheavy load.

Another object is to provide a new and improved flywheel type magneto ofthe type set forth which produces such adequate voltage without thenecessity that the ad- Vance mechanism be set for excessively highspeeds.

Another object is to provide a new and improved flywheel type magneto ofthe type set forth which is particularly adapted to provide highignition voltage in any normal designed range of advance, for example,fifteen degrees to twenty-five degrees or more.

Another object of the invention is to provide a new and improvedflywheel type magneto of the type set forth which is both simple toapply to engines and economical to manufacture.

Other objects and advantages of the invention will be apparent from thefollowing description taken in connection with the accompanyingdrawings. It will be understood that changes may be made in the detailsof construction and arrangement of parts shown and described as thepreferred form of the invention has been given by way of illustrationonly.

Referring to the drawings:

FIG. 1 is a fragmentary top view of a flywheel type magneto embodyingthe present invention;

FIG. 2 is a sectional view taken on line 2-2 of FIG. 1, looking in thedirection of the arrows;

FIG. 3 is a fragmentary bottom view of the device shown in FIGS. 1 and2; and

FIG. 4 is a schematic view of the electrical system of the apparatus.

Referring more particularly to the drawings wherein similar referencecharacters designate corresponding parts throughout, the device showntherein comprises a low tension flywheel type magneto having a statorand a rotor 11, said rotor 11 carrying the magnet 13 and the 3,252,021Patented May 17, 1966 associated pole pieces 14 and being mounted forrotary movement upon the engine crankshaft or shaft 12 which is adaptedto be rotated in timed relationship with the engine.

The stator 10 is provided with a three legged or poled laminatedmagnetic structure or core 15 having low ten sion primary generatingcoils or windings 16 upon the first two legs thereof in the direction ofrotation of the rotor 11, said two windings 16 being connected inseries.

Said two coils or windings 16 may be identical or may be tailored forspecial engine operating requirements.

The capacitator 17 and the breaker 18, which is operated by the cam 19,are connected across the stator windings 16 and the high tension step-uptransformer 20 is connected across said breaker 18 and said windings 16and in parallel with said stator windings 16.

Any conventional means may be used to advance, either mechanically orautomatically, the timing of the device and to change the phase relationbetween the cam 19 and the crankshaft 12. An example of such means is,for example, that disclosed in United States Patent Number 2,806,156 toR. E. Phelon where the breaker cam is connected to the shaft by means ofa rotatably adjustable sleeve, which sleeve is adjustable relative tosaid a shaft, such that advance or retardment may be obtained as thespeed of the engine increases or decreases.

In the operation of the foredescribed magneto, at starting the magnetooperates normally. At low speed operation, the magneto breaks on thereversal of flux in the coil or winding 16 on the middle leg of thelaminated magnetic structure 15 carried by the stator 10. During thisperiod, the second or other primary coil 16 is merely in series withsaid working primary coil 16, and, being open circuited magnetically andhaving low impedance, it has little effect on the final voltage outputof the device.

When the cam 19 is advanced, whether mechanically or automatically, thebreak occurs on the buildup and less voltage will, of course, begenerated in a given primary coil.

Thus, the second primary coil 16 on the leading leg of the structure 15,which is connected in series with the center primary coil 16, willgenerate an equal voltage and, in effect, double the effective inducedvoltage in the total primary circuit as, in the advanced position, thetwo windings 16 upon the laminated structure or core 15 will begenerating simultaneously.

From the foregoing, it will be seen that we have provided a new andimproved high output flywheel type magneto with automatic spark advance,and high output at all speeds of the cam.

From the foregoing, it will be seen that we have provided new andimproved means for accomplishing all of the objects and advantages ofthe invention.

We claim:

1. In a flywheel magneto having a stator and a rotor, a magnet carriedby said rotor, pole shoes carried by said rotor and operativelyassociated with said magnet, a three legged laminated magnetic structureon said stator and operatively positioned thereon with regard to saidmagnet on said rotor, windings upon the first two legs of said laminatedmagnetic structure to be engaged by said rotor magnet and associatedpole shoes during the operation of the magneto, said windings beingconnected in series, and a transformer connected in parallel with saidwindings on said magnetic structure.

2. In a flywheel magneto having a stator and a rotor, said rotor beingmounted for rotary movement upon a crankshaft, a magnet carried by saidrotor, pole shoes carried by said rotor and operatively associated withsaid magnet, a three legged laminated magnetic structure on said statorand operatively positioned thereon with regard to said magnet on saidrotor, windings upon the first two legs of said laminated magneticstructure to be engaged by said rotor magnet and associated pole shoesduring the operation of the magneto, said windings being connected inseries, a transformer connected in parallel with said windings onsaidmagnetic structure, and a breaker connected across said windings, a camoperatively connected to and operating said breaker, and means forchanging the phase relationship between said cam and said magnetocrankshaft.

3. In a flywheel'magneto having a stator and a rotor, a magnet carriedby said rotor, pole pieces carried by said rotor and operativelyassociated with said magnet, a three poled laminated magnetic structureon said stator and operatively positioned thereon relative to saidmagnet on said rotor, windings upon the first two poles of saidlaminated magnetic structure to be engaged by said rotor magnet andassociated pole pieces during the operation of the magneto, said twowindings being connected in series, and a transformer connected inparallel with said stator windings.

4. In a flywheel magneto having a stator and a rotor, said rotor beingmounted for rotation upon a crankshaft, a magnet carried by said rotor,pole pieces carried by said rotor and operatively associated with saidmagnet, a three poled laminated magnetic structure on said stator andoperatively positioned thereon relative to said magnet on said rotor,windings upon the first two poles of said laminated magnetic structureto be engaged by said rotor magnet and associated pole pieces during theoperation of the magneto, said two windings being connected in series, atransformer connected in parallel with said windings, a breakerconnected across said windings, a cam operatively connected to andoperating said breaker, and means for changing the phase relationshipbetween said cam and said magneto crankshaft.

5. In a flywheel magneto having a stator and a rotor, a magnet carriedby said rotor, pole pieces carried by said rotor and operativelyassociated with said magnet,

} magnet, a three legged laminated magnetic structure on a three leggedlaminated magnetic structure on said stator and operatively positionedthereon relative to said magnet on said rotor, windings upon the firsttwo legs of said three legged structure to be engaged by said rotormagnet and associated pole pieces during the operation of the magneto,said two windings being connected in series, and a high tensiontransformer connected in parallel with said windings.

6. In a flywheel magneto having a stator and a rotor, said rotor beingmounted for rotary movement upon a crankshaft, a magnet carried by saidrotor, pole pieces carried by said rotor and operatively associated withsaid said stator and operatively positioned thereon relative to saidmagnet on said rotor, windings upon the two leading legs of said threelegged laminated structure, said two windings being connected in series,a high tension transformer connected in parallel with said windings, a

breaker connected across said windings, a cam operatively connected tosaid breaker such as to operate said breaker, and means for changing thephase relationship between said cam and said magneto crankshaft.

References Cited by the Examiner r ORIS L. RADER, Primary Examiner.

MILTON O. HIRSHFIELD, Examiner.

A. I. ROSSI, Assistant Examiner.

1. IN A FLYWHEEL MAGNETO HAVING A STATOR AND A ROTOR, A MAGNET CARRIEDBY SAID ROTOR, POLE SHOES CARRIED BY SAID ROTOR AND OPERATIVELYASSOCIATED WITH SAID MAGNET, A THREE LEGGED LAMINATED MAGNETIC STRUCTUREON SAID STATOR AND OPERATIVELY POSITIONED THEREON WITH REGARD TO SAIDMAGNET ON SAID ROTOR, WINDINGS UPON THE FIRST TWO LEGS OF SAID LAMINATEDMAGNETIC STRUCTURE TO BE ENGAGED BY SAID ROTOR